scholarly journals Genome Plasticity a Key Factor in the Success of Polyploid Wheat Under Domestication

Science ◽  
2007 ◽  
Vol 316 (5833) ◽  
pp. 1862-1866 ◽  
Author(s):  
J. Dubcovsky ◽  
J. Dvorak
2018 ◽  
Author(s):  
Itamar Sela ◽  
Yuri I. Wolf ◽  
Eugene V. Koonin

In prokaryotic genomes, the number of genes that belong to distinct functional classes shows apparent universal scaling with the total number of genes [1–5] (Fig. 1). This scaling can be approximated with a power law, where the scaling power can be sublinear, near-linear or super-linear. Scaling laws are robust under various statistical tests [4], across different databases and for different gene classifications [1–5]. Several models aimed at explaining the observed scaling laws have been proposed, primarily, based on the specifics of the respective biological functions [1, 5–8]. However, a coherent theory to explain the emergence of scaling within the framework of population genetics is lacking. We employ a simple mathematical model for prokaryotic genome evolution [9] which, together with the analysis of 34 clusters of closely related microbial genomes [10], allows us to identify the underlying forces that dictate genome content evolution. In addition to the scaling of the number of genes in different functional classes, we explore gene contents divergence to characterize the evolutionary processes acting upon genomes [11]. We find that evolution of the gene content is dominated by two factors that are specific to a functional class, namely, selection landscape and genome plasticity. Selection landscape quantifies the fitness cost that is associated with deletion of a gene in a given functional class or the advantage of successful incorporation of an additional gene. Genome plasticity, that can be considered a measure of evolvability, reflects both the availability of the genes of a given functional class in the external gene pool that is accessible to the evolving microbial population, and the ability of microbial genomes to accommodate these genes. The selection landscape determines the gene loss rate, and genome plasticity is the principal determinant of the gene gain rate.


Author(s):  
J. E. Laffoon ◽  
R. L. Anderson ◽  
J. C. Keller ◽  
C. D. Wu-Yuan

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).


2020 ◽  
Vol 51 (3) ◽  
pp. 509-513
Author(s):  
Ashley Bourque Meaux ◽  
Julie A. Wolter ◽  
Ginger G. Collins

Purpose This article introduces the Language, Speech, and Hearing Services in Schools Forum: Morphological Awareness as a Key Factor in Language-Literacy Success for Academic Achievement. The goal of this forum is to relate the influence morphological awareness (MA) has on overall language and literacy development with morphology acting as the “binding agent” between orthography, phonology, and semantics ( Perfetti, 2007 ) in assessment and intervention for school-aged children. Method This introduction provides a foundation for MA development and explores the influence MA has over the course of school-aged language and literacy development. Through summaries of the 11 articles in this forum, school-based speech-language pathologists will be able to convey the importance of MA to promote successful educational outcomes for kindergarten to adolescent students. The forum explores researcher-developed assessments used to help identify MA skill level in first- through eighth-grade students at risk for literacy failure to support instructional needs. The forum also provides school-based speech-language pathologists with details to design and implement MA interventions to support academic success for school-aged students with varying speech-language needs (e.g., dual language emersion, vocabulary development, reading comprehension) using various service delivery models (e.g., small group, classroom-based, intensive summer camps). Conclusion MA is effective in facilitating language and literacy development and as such can be an ideally focused on using multilinguistic approaches for assessment and intervention. The articles in this issue highlight the importance in assessment measures and intervention approaches that focus on students' MA to improve overall academic success in children of all ages and abilities.


2005 ◽  
Vol 173 (4S) ◽  
pp. 393-393
Author(s):  
Bunzo Kashiwagi ◽  
Yasuhiro Shibata ◽  
Kazunari Ohki ◽  
Seiji Arai ◽  
Seijiro Honma ◽  
...  

2011 ◽  
Author(s):  
Landon Ranck ◽  
Faith Clasby ◽  
Tor Ekstrom ◽  
Rebecca Ross ◽  
Claire Lawes ◽  
...  
Keyword(s):  

2009 ◽  
pp. 54-69 ◽  
Author(s):  
A. Shastitko ◽  
S. Avdasheva ◽  
S. Golovanova

The analysis of competition policy under economic crisis is motivated by the fact that competition is a key factor for the level of productivity. The latter, in its turn, influences the scope and length of economic recession. In many Russian markets buyers' gains decline because of the weakness of competition, since suppliers are reluctant to cut prices in spite of the decreasing demand. Data on prices in Russia and abroad in the second half of 2008 show asymmetric price rigidity. At least two questions are important under economic crisis: the 'division of labor' between pro-active and protective tools of competition policy and the impact of anti-crisis policy on competition. Protective competition policy is insufficient in transition economy, especially in the days of crisis it should be supplemented with the well-designed industrial policy measures which do not contradict the goals of competition. The preferable tools of anti-crisis policy are also those that do not restrain competition.


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